Fog and rain are dangerous conditions in which to drive and often produce accidents because drivers cannot see as far ahead and because both conditions adversely affects the driver's ability to properly judge speed and distance; they affect perception. The effects are the result of reduced contrast. People see objects, not based on their absolute brightness or darkness, but on their perception of the difference between the object's brightness and that of its background. Fog and rain lower contrast considerably, causing objects to appear fainter and less distinct to the observer.
Fog forms when water vapor in the air at the surface begins to condense into liquid water. Fog formation requires all of the elements that normal cloud formation requires with the most important being condensation nuclei. When the air is saturated, additional moisture tends to condense rather than staying in the air as vapor. Condensation nuclei must be present in the form of dust, aerosols, pollutants, etc. around which water condenses forming tiny droplets we see as fog.
As light travels through the air, it is affected by these moisture droplets and other objects in its path. Atoms and molecules in the air, including anything carried in the air like dust, smoke and water, will cause light to “scatter”. Scattering is the angular redistribution of a portion of an incident light beam when it strikes a rough surface or a cloud of small particles, like fog. Put another way, when light strikes the moisture droplets, only a portion passes through while the rest scatters. Fog and rain therefore block some of the light reflected by objects and less reaches the driver's eye. Water droplets scatter light extremely well, especially when they are small as is the case with fog.
When we drive, the light falling on objects around us, such as the road, other cars, pedestrians, traffic control devices, etc. is reflected to us as the viewer. If there is little or no scattering of light, the images we see are clear and highly contrasted with the background. In fog and rain conditions, the light falling on these objects and reflected to us is scattered before it reaches us. In many instances, the scattered light produced by fog and rain reduces visibility to only a few meters or so creating an incredibly dangerous condition.
Heretofore, a variety of apparatus have been developed to improve visibility of objects in fog and rain conditions. Fog light technology and windshield wipers can lend some relief to the driver's obstructed view; however, both can be very limited in application. More high-tech means of “seeing through fog” using thermal imaging, infrared, sonar or even GPS technologies have also been developed but are not within financial reach of everyday consumers.
The following U.S. utility patents and pending applications relate to windshield modification or the reflecting of light or glare at the windshield: 20090116098 dated May, 2009 entitled, Device for Adjusting the Tint of Glass; U.S. Pat. No. 7,309,096 dated December, 2007 entitled, Visibility Adjusting Method and Apparatus of Vehicle; U.S. Pat. No. 7,133,206 dated November, 2006 entitled, Reflecting Surface Material; U.S. Pat. No. 7,100,960 dated September, 2006 entitled, Visibility Adjusting Method and Apparatus of Vehicle; U.S. Pat. No. 6,746,126 dated June, 2004 entitled, Vehicle Interior Trim Having a Reduced Glare Effect at the Windshield and the Rear View Window; U.S. Pat. No. 6,056,397 dated May, 2000 entitled, Method and Apparatus for Reducing Glare While Driving; U.S. Pat. No. 5,335,099 dated August, 1994 entitled, Veiling Glare Control Holographic Windshield; U.S. Pat. No. 5,316,359 dated May, 1994 entitled, Anti-Reflective Automotive Interior Instrument Panel Surface; U.S. Pat. No. 4,756,603 dated July, 1988 entitled, Glare Proof Transparent Cover Plate; and U.S. Pat. No. 3,679,887 dated July, 1972 entitled, Light Reflection Preventive Device.
A next group of patents relating to glare shields and related attachments for visors are as follows: U.S. Pat. No. 5,613,725 dated March, 1997 entitled, Glare Shield Device; U.S. Pat. No. 5,613,724 dated March, 1997 entitled, Glare Reduction Visor for Vehicles; U.S. Pat. No. 4,635,995 dated January, 1987 entitled Detachably Mounted Add On Sun Visor for Vehicles; U.S. Pat. No. 3,837,703 dated September, 1974 entitled, Glare Shields and U.S. Pat. No. 3,697,255 dated July, 1972 entitled, Mounting Means for Windshield Light Filter.
Finally, the following patents and patent applications relate to filter, lens cover and reflector technology, but do not pertain to windshield-based apparatus or methods as does the subject invention: U.S. Pat. No. 7,471,358 dated December, 2008 entitled, Liquid Crystal Display Device; 20070217010 dated September, 2007 entitled, Reducing Reflection; 20070216836 dated September, 2007 entitled, Reducing Reflection; U.S. Pat. No. 6,299,231 dated October, 2001 entitled, Veiling Glare Reduction System; U.S. Pat. No. 5,848,840 dated December, 1998 entitled, Emergency Fog Lens Device; and U.S. Pat. No. 3,754,135 dated August, 1973 entitled, Light Treating Means.
Most of the above identified patents related to methods and apparatus for reducing or eliminating the reflection of light onto a windshield (i.e., glare). The invention herein is intended to do the opposite, that is, to impart a reflection of specific character onto a portion of the windshield through which said reflection objects in fog may be seen with greater clarity and contrast.
All patents, patent applications, provisional applications, and publications referred to or cited herein, or from which a claim for benefit of priority has been made, are incorporated herein by reference in their entirety to the extent they are not inconsistent with the explicit teachings of this specification.